A184665 Number of (n+1) X 2 0..3 arrays with no 2 X 2 subblock summing to less than 6.

150, 1740, 19269, 216912, 2430631, 27278035, 305991368, 3432961182, 38513146024, 432071200891, 4847297854288, 54380688812185, 610083824961241, 6844384156411424, 76785501492801006, 861438105302681684

Offset

1,1

Comments

Column 1 of A184673.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 10*a(n-1) + 25*a(n-2) - 123*a(n-3) - 73*a(n-4) + 304*a(n-5) + 36*a(n-6) - 144*a(n-7).

Empirical g.f.: x*(150 + 240*x - 1881*x^2 - 828*x^3 + 4756*x^4 + 432*x^5 - 2304*x^6) / (1 - 10*x - 25*x^2 + 123*x^3 + 73*x^4 - 304*x^5 - 36*x^6 + 144*x^7). - Colin Barker, Feb 27 2018

Example

Some solutions for 3 X 2:
..0..1....0..0....2..0....2..1....3..2....0..2....1..3....3..1....3..0....3..1
..2..3....3..3....3..3....2..1....1..3....3..3....3..1....3..1....2..3....3..3
..0..1....2..0....3..3....1..2....2..2....2..1....3..1....3..1....2..1....1..0

Crossrefs

Cf. A184673.

Sequence in context: A073614 A191547 A184673 * A088361 A206041 A151607

Adjacent sequences: A184662 A184663 A184664 * A184666 A184667 A184668

Keyword

nonn

Author

R. H. Hardin, Jan 19 2011

Status

approved